Pulsator pumps



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INVENTo JERZY J. CZARNECKI ATTORNEY Aug. 15, 1957 J. J. czARNEcKl 3,335,655

PULSATOR- PUMPS Filed Jan. 5, 1966 5 sheets-sheet s ATTORNEYS United States Patent O v 3,335,666 PULSATR PUMPS .Ierzy .1. Czarneclri, Princeton, NJ., assignor to De Laval Turbine Inc., Trenton, NJ., a corporation of Delaware Filed Jan. 5, 1966, Ser. No. 518,862 7 Claims. (Cl. 103-44) This invention relates to pulsator pumps of the type in which there is provided an elastic membrane separating a driving iluid from a pumped uid, and particularly to improvements in the assembly of the core which is conventionally provided within the elastic member on the driving fluid side.

Pumps of the pulsator type are particularly suited for handling corrosive liquids, slurrys and the like since the elastic membrane (hereafter referred to as the pulsator) prevents the pumped uid from entering into and damaging parts of the driving system. Pumps of this type are generally provided with oil in their driving systems, and oil is introduced into the interior of the pulsator under pressure originating from a suitable driving pump such as the pump described in Patent 1,965,557, issued Iuly 3, 1934.

Pulsators are generally operated in pairs, and alternately so that a continuous flow is produced at an outlet. Alternation of the operation of the pulsators is effected by providing a phasing valve which directs driving oil from the driving pump into the interior of one pulsator and then to the other so that one pulsator is permitted to contract while the other expands. A typical phasing valve of a type suitable for use in conjunction with a pair of pulsators is disclosed in United States Patent 2,836,121, issued May 27, 1958.

In the last-mentioned patent, a typical pulsator core is disclosed. This core is in the form of a cylinder closed at one end and provided with a plurality of transverse openings which permits the passage of driving oil to expand the pulsator.

In a pumping system, each pulsator is typically provided with a pair of one-way check valves, one of which permits entrance of pumped fluid into a pumping chamber surrounding the pulsator, and the other of which permits the pumped iluid to exit from the pumping chamber. It will be readily apparent that failure of the exit check valve to close when the pulsator with which it is associated is contracting can result in damage to the pulsator particularly where the product pressure is high. Since, during the time at which the pulsator is contracting, the interior of the pulsator is opened to atmospheric pressure by the phasing valve, `a high pressure differential exists across the pulsator membrane, and can cause extrusion of the membrane through the openings provided in the core. In consequence, perforations will be produced in the pulsator which render it useless since driving oil is permitted to pass through the perforations into the pumped fluid chamber. Damage of the same nature can occur when the product pressure is relatively high before it enters the pumped fluid chamber. Such a situation might exist, for example, where the pump is used for transferring water from the ballast tanks of a submarine.

In general, the invention involves the provision of valve means in association with the pulsator core. This valve means closes when the pressure differential across the pulsator membrane becomes too great. Driving oil, which is practically incompressible, is trapped between the pulsator membrane and the core, so that the membrane cannot be extruded through the perforations in the core.

The object of the invention is therefore to provide a pulsator core assembly which cannot cause damage to the pulsator as a result of a high pressure differential 3,335,665 Patented Aug. l5, 1967 ICC across the pulsator, when the condition.

Other objects will be apparent from the following description when read in conjunction with the accompanying drawings in which:

FIGURE l is a vertical section through a single pulsator assembly which is provided with a core assembly in accordance with the present invention;

FIGURE 2 is an elevation of the core assembly of FIGURE 1;

FIGURE 3 is a section of the core assembly taken on the plane, the trace of which is indicated at 3-3 in FIGURE 2;

FIGURE 4 is a partially diagrammatic elevation of a pumping system in accordance with the invention;

FIGURE 5 is a vertical section of a core assembly in accordance with an alternative embodiment of the invention;

FIGURE 6 is a section of the pulsator shown in FIG- URE 5 taken on the plane, the trace of which is indicated at 6 6;

FIGURE 7 is a vertical section of a core assembly in accordance with an alternative embodiment of the invention;

FIGURE 8 is a section of the pulsator shown in FIG- URE 7 taken on the plane, the trace of which is indicated at 8 8;

FIGURE 9 is a vertical section of a core assembly in accordance with an alternative embodiment of the invention; and

FIGURE 10 is a section of the pulsator shown in FIG- URE 9 taken on the plane, the trace of which is indicated at 10-10.

Referring to FIGURE l, a housing member 12 is shown, which is desirably provided with a cylindrical bore 14. A top plate 16 is bolted to a flange 18 integral with the housing member, and a suitable sealing ring 2o is providedin a circular groove in member 12 and is held in compression by top plate 16.

A pulsator 22 in the shape of an elongated thimble and desirably formed of a synthetic elastomer capable of withstanding lubricating oil, is provided within bore 14 of the housing, and is attached at its open end to a member 24 which is xed to the top plate by means of bolts 26. A sealing ring 28 is provided between member 24 and the interior wall of housing 12.

A driving liquid inlet passage is provided in top plate 16 by means of a pipe 3l) to which is attached a suitable connecting ange 32.

At the lower end of the housing, there is provided a closure 34. A pumped iluid inlet port 36 is provided communicating through passage 38 with the interior of the housing. A one-way check valve comprising ball 4613 and seat 42 is provided in passage 38 to permit flow of pumped fluid only toward the interior of the pumping chamber. A similar one-way check valve comprising ball 44 and seat 46 is provided in an outlet passage 48 leading to the exterior through port 5t). Pins 52 are provided in association with each of the check valves in order to limit movement of balls 40 and 44.

An inner member 54 of the pulsator core assembly generally indicated at 56 is suitably attached to top plate 16 as by welding indicated at 58. Member 54 is provided with a spring retaining flange 60 near its upper end. A central passage 62 is provided throughout the length of member 54, and transverse passages 64 are provided for lubrication. A plurality of transverse passages 66 are provided in member 54 in order to permit passage of driving oil to the interior of pulsator 22. A transverse passage 68 is provided, as will be explained later, to accommodate an aligning pin 70. An axial lubricating passage 72 is provided at the end of member 54.

pulsator is in its collapsed An outer core member 74, which is generally cylindrical in form is arranged to slide in an axial direction on inner member 54. A shoulder portion 76 is provided in the interioriof member 74, and a helical spring 78 is compressed between shoulder 76 and ange 60. At the bottom of the bore through member 74 there is provided a retaining member 80 and a helical spring S2 compressed between member 80 and the lower end of inner core member 54.

A plurality of openings 84 is provided in member 74, and these openings are normally aligned with corresponding openings 66 in member 54, so that passage of driving oil is permitted through the corresponding passages to the interior of the pulsator. Pin 70, which engages the wall of passage 68 prevents rotation of outer core member 74 with respect to the inner core member so that the corresponding passages 66 and 84 remain in radial alignment. A plurality of axially extending grooves 86 is provided in member 74, as illustrated in FIGURES 2 and 3. Driving oil openings -84 are located in the bottom of these grooves.

Referring to FIGURE 4, a pumping system comprising two pulsators is shown. A driving pump 88, desirably of the positive screw type receives -oil from passage 90, and delivers the oil under pressure through passage 92 to a phasing valve 94 which alternately delivers the driving oil through passages 96 and 98. Phasing valve 94 is also provided with passages 100 and 102 which desirably lead to a driving oil reservoir. Phasing valve 94 connects passage 96 to passage 100 when passage 98 is connected to the driving pump through passage 92, and passage 102 is connected to passage 98 during the part of the pumping cycle during which the driving pump is connected to passage 96. Passages 100 and 102 therefore empty their associated pulsators within housings 12 and 12a when the pulsators are contracting. Inlet ports 36 and 36a on the respective pumps are connected together through line 104 which receives pumped uid through line 106. Likewise, outlet ports 50 and 50a are connected together through line 108 which delivers pumped fluid through line 110. Because of the alternate operation of the pulsators, it will be apparent that substantially continuous ow of pumped luid can be obtained.

The vertical grooves 86 illustrated in FIGURES 2 and 3 act to prevent damage to the pulsator when a small pressure diferential exists across the pulsator forcing it in the collapsed direction. The pulsator is forced into the grooves so that it is caused to stretch circumferentially. This stretching presents a resistance which tends to balance ot the applied pressure differential. When only a minor pressure differential exists, it is not necessary that the passages 84 be closed ott to entrap driving liquid between the pulsator and the core, since the pulsator lwill not contact the outer ends of passages 84, or if such contact is made, it will not be with suficient force to damage the pulsator.

If the pressure differential is great, however, grooves 86 will not be suflicient to prevent damage to the pulsator, and it is necessary to entrap driving liquid between the pulsator and the core. Referring to FIGURES l and 3, the necessary entrapment is accomplished by axial displacement of core member 74 with respect to the inner core member 54. Coil springs 78 and 82 urge member 74 in the downward direction so that retaining pin 70 engages the lower part of passage 68 which determines the lower limit of movement of core member 74. The compression of the coil springs is so chosen that an abnormal pressure differential across the pulsator will cause member 74 to be moved upwardly so that passages 84 and 66 are moved out of alignment with one another causing complete closure of the space between the pulsator and the core to driving liquid passage 62. Driving liquid is thus trapped in grooves 86, and extrusion of the pulsator through passages 84 cannot occur. The pulsator is supported by a xed volume of relatively incompressible liquid. As soon as driving liquid is again introduced through passage 30 into passage 62 to expand the pulsator, outer core member 74 drops to its normal position so that passages 66 and 84 are realigned.

Referring to FIGURES 5 and 6, an alternative embodiment of the invention is shown. Only the assembly including the core and the pulsator is illustrated, it being understood that the remainder of the pump can be identical to that illustrated in FIGURE l.

A thimble-shaped pulsator 112 surrounds a core assembly indicated generally at 114. The core is fixed at its upper end so that it cannot move vertically with respect to the pulsator. A central passage 116 is provided to receive driving liquid under pressure from a suitable source. Passage 116 is terminated at 118 near the lower end of the core. The cross-section of the core is generally in the form of a rectangle with rounded corners as illustrated in FIGURE 6, 4although it will be recognized that any configuration having substantially smooth areas about its periphery will be suitable. Driving liquid passages 120 are provided in a transverse direction through the wall of the core, and terminate at their outer ends in the at areas on the outer surface of the core. A valve comprising a ring 122 slidable on the surface of the core for convenience of assembly and having a plurality of reeds 124 ex,- tending axially therefrom is provided on the core. The ring 122 and reeds are of spring metal. Reeds 124 are bent slightly outwardly from the ring at 126 so that they normally permit free passage of driving liquid through the passages 120 with which they are aligned. Each reed 124 is aligned with a vertical row of passages 120 so that passages 120 will be closed off by the reeds when they are ilexed inwardly by the pulsator under the action of a pressure diiferential tending to collapse the pulsator. By this arrangement, the material -of which the pulsator is formed cannot be forced into the holes under the high pressure differential which may exist between the product pressure and the pressure of the driving liquid. When the reeds are forced inwardly a continuous metal surface is presented to the pulsator.

FIGURES 7 and 8 show a pulsator core 128 provided with a pair of reed valves comprising metallic ring members 130 and 132 having integral reeds 134 and 136 respectively extending in opposite directions. Each reed closes three holes 138 provided in columns of six.

Referring to FIGURES 9 and 10, an alternative assembly is shown in which there is provided a core member 140 which is substantially rectangular in cross-section. Grooves 142 are provided on the exterior of the core in alignment with central passage 144. Transverse passages 146 lead from passage 144 to the exterior of the core and terminate in the grooves. Valve assemblies 148 and 150, are provided about the core and have multiple reeds 152 which are bent into grooves `142 but which are normally sprung away from the outer ends of passages 146, and which lie in grooves 142 so that a more substantial pressure differential is required to cause `reeds 152 to close oif the transverse passages. The pressure differential mustbe sufficient to cause the pulsator 154 which surrounds the core to bend inwardly so that it contacts the reeds 152 and forces them against the bottoms of the grooves.

It will be apparent that closure of the transverse passages in the assemblies shown in FIGURES 5, 6, 7 and 8 may occur each time the pulsator collapses, while an abnomal pressure differential will be required in order to close the transverse passages of the apparatus of FIG- URES 9 and l0. The core assemblies shown in FIGURES 5-10 prevent extrusion of the pulsator through holes in the core by blocking the holes at their exteriors rather` than by trapping driving liquid between the pulsator and the core, although a small quantity of liquid may be trapped incidentally depending on the configuration of the reed valve assembly.

It will be apparent that various departures may be made from what is speciiically disclosed herein and that modiiications may be made without departing from the invention as defined in the following claims.

What is claimed is:

1. A pump comprising means defining a pumping chamber, valved means for directing the iiow of pumped uid into and out of said chamber, a pulsator formed of an elastic material disposed Within said chamber, core means supporting said pulsator against collapse, said core means having openings permitting driving liquid to pass inwardly and outwardly through said openings, a source of driving liquid under pressure, and means alternately directing driving liquid through said openings to expand said pulsator and permitting driving liquid to exit through said openings to permit contraction of said pulsator, said core means including valve means operable when the pressure differential across said pulsator reaches a predetermined value to close said openings.

2. A pump according to claim 1 in which said core means comprises an inner member and an outer member, said members being slidable with respect to each Other and having normally aligned passages permitting flow of driving liquid therethrough, but movable so that the normally aligned passages are moved out of alignment when the pressure diierential across said pulsator reaches said predetermined value.

3. A pump according to claim 2 in which a spring normally holds said core members in ow permitting relative positions, and in which their relative positions to prevent flow involves action against the spring.

4. A pump according to claim 1 in which said core means has exterior grooves with which said openings communicate.

5. A pump according to claim 1 in which each of said core openings is associated with a exible member normally spaced from the opening but arranged to be moved towards the opening to close the same under the action of the pulsator when said pressure differential reaches said predetermined value.

`6. A pump according to claim 5 in which said exible member lies in a groove.

7. A pump comprising means defining a pumping chamber, valve means for directing the How 0f pumped uid into and out of said chamber, a pulsator formed of an elastic material disposed Within said chamber, and core means supporting said pulsator from within, said core means having a central passage for receiving driving liquid and transverse passages permitting the flow of driving liquid from said central passage to the exterior of said core means, said transverse passages terminating in grooves provided in the exterior of said core means.

References Cited UNITED STATES PATENTS 1,389,635 9/1921 Dunkle. 2,196,993 4/ 1940 Kidder 103-44 2,738,731 3/1956` v Browne 10344 ROBERT M. WALKER, Primary Examiner. 

1. A PUMP COMPRISING MEANS DEFINING A PUMPING CHAMBER, VALVED MEANS FOR DIRECTING THE FLOW OF PUMPED FLUID INTO AND OUT OF SAID CHAMBER, A PULSATOR FORMED OF AN ELASTIC MATERIAL DISPOSED WITHIN SAID CHAMBER, CORE MEANS SUPPORTING SAID PULSATOR AGAINST COLLAPSE, SAID CORE MEANS HAVING OPENINGS PERMITTING DRIVING LIQUID TO PASS INWARDLY AND OUTWARDLY THROUGH SAID OPENINGS, A SOURCE OF DRIVING LIQUID UNDER PRESSURE, AND MEANS ALTERNATELY DIRECTING DRIVING LIQUID THROUGH SAID OPENINGS TO EXPAND SAID PULSATOR AND PERMITTING DRIVING LIQUID TO EXIT THROUGH SAID OPENINGS TO PERMIT CONTRACTION OF SAID PULSATOR, SAID CORE MEANS INCLUDING VALVE MEANS OPERABLE WHEN THE PRESSURE DIFFERENTIAL ACROSS SAID PULSATOR REACHES A PREDETERMINED VALUE TO CLOSE SAID OPENINGS. 